Is that even true? I thought it was, because I remember that being the rumor since before it was announced, and also REmake 3 came out so close after REmake 2. But if you actually look at who's listed as the developer, it's Capcom themselves. The guy directing it is even the chief programmer of RE3 and RE4 (originals).
A small team at Capcom lead the project, but most of the work was done by three 3rd party studios from what I understand; K2 Inc, M-Two, and Redworks.